package lnwire

import (
	"bytes"
	"encoding/binary"
	"encoding/hex"
	"io"
	"reflect"
	"testing"

	"github.com/davecgh/go-spew/spew"
	"github.com/lightningnetwork/lnd/fn"
	"github.com/stretchr/testify/require"
)

var (
	testOnionHash     = [OnionPacketSize]byte{}
	testAmount        = MilliSatoshi(1)
	testCtlvExpiry    = uint32(2)
	testFlags         = uint16(2)
	testType          = uint64(3)
	testOffset        = uint16(24)
	sig, _            = NewSigFromSignature(testSig)
	testChannelUpdate = ChannelUpdate1{
		Signature:       sig,
		ShortChannelID:  NewShortChanIDFromInt(1),
		Timestamp:       1,
		MessageFlags:    0,
		ChannelFlags:    1,
		ExtraOpaqueData: make([]byte, 0),
	}
)

var onionFailures = []FailureMessage{
	&FailInvalidRealm{},
	&FailTemporaryNodeFailure{},
	&FailPermanentNodeFailure{},
	&FailRequiredNodeFeatureMissing{},
	&FailPermanentChannelFailure{},
	&FailRequiredChannelFeatureMissing{},
	&FailUnknownNextPeer{},
	&FailIncorrectPaymentAmount{},
	&FailFinalExpiryTooSoon{},
	&FailMPPTimeout{},

	NewFailIncorrectDetails(99, 100),
	NewInvalidOnionVersion(testOnionHash[:]),
	NewInvalidOnionHmac(testOnionHash[:]),
	NewInvalidOnionKey(testOnionHash[:]),
	NewTemporaryChannelFailure(&testChannelUpdate),
	NewTemporaryChannelFailure(nil),
	NewAmountBelowMinimum(testAmount, testChannelUpdate),
	NewFeeInsufficient(testAmount, testChannelUpdate),
	NewIncorrectCltvExpiry(testCtlvExpiry, testChannelUpdate),
	NewExpiryTooSoon(testChannelUpdate),
	NewChannelDisabled(testFlags, testChannelUpdate),
	NewFinalIncorrectCltvExpiry(testCtlvExpiry),
	NewFinalIncorrectHtlcAmount(testAmount),
	NewInvalidOnionPayload(testType, testOffset),
	NewInvalidBlinding(fn.Some(testOnionHash)),
}

// TestEncodeDecodeCode tests the ability of onion errors to be properly encoded
// and decoded.
func TestEncodeDecodeCode(t *testing.T) {
	for _, failure1 := range onionFailures {
		var b bytes.Buffer

		if err := EncodeFailure(&b, failure1, 0); err != nil {
			t.Fatalf("unable to encode failure code(%v): %v",
				failure1.Code(), err)
		}

		failure2, err := DecodeFailure(&b, 0)
		if err != nil {
			t.Fatalf("unable to decode failure code(%v): %v",
				failure1.Code(), err)
		}

		if !reflect.DeepEqual(failure1, failure2) {
			t.Fatalf("expected %v, got %v", spew.Sdump(failure1),
				spew.Sdump(failure2))
		}
	}
}

// TestEncodeDecodeTlv tests the ability of onion errors to be properly encoded
// and decoded with tlv data present.
func TestEncodeDecodeTlv(t *testing.T) {
	t.Parallel()

	for _, testFailure := range onionFailures {
		testFailure := testFailure
		code := testFailure.Code().String()

		t.Run(code, func(t *testing.T) {
			t.Parallel()

			testEncodeDecodeTlv(t, testFailure)
		})
	}
}

var testTlv, _ = hex.DecodeString("fd023104deadbeef")

func testEncodeDecodeTlv(t *testing.T, testFailure FailureMessage) {
	var failureMessageBuffer bytes.Buffer

	err := EncodeFailureMessage(&failureMessageBuffer, testFailure, 0)
	require.NoError(t, err)

	failureMessageBuffer.Write(testTlv)

	failure, err := DecodeFailureMessage(&failureMessageBuffer, 0)
	require.NoError(t, err)

	// FailIncorrectDetails already reads tlv data. Adapt the expected data.
	if incorrectDetails, ok := testFailure.(*FailIncorrectDetails); ok {
		incorrectDetails.extraOpaqueData = testTlv
	}

	require.Equal(t, testFailure, failure)
}

// TestChannelUpdateCompatibilityParsing tests that we're able to properly read
// out channel update messages encoded in an onion error payload that was
// written in the legacy (type prefixed) format.
func TestChannelUpdateCompatibilityParsing(t *testing.T) {
	t.Parallel()

	// We'll start by taking out test channel update, and encoding it into
	// a set of raw bytes.
	var b bytes.Buffer
	if err := testChannelUpdate.Encode(&b, 0); err != nil {
		t.Fatalf("unable to encode chan update: %v", err)
	}

	// Now that we have the set of bytes encoded, we'll ensure that we're
	// able to decode it using our compatibility method, as it's a regular
	// encoded channel update message.
	var newChanUpdate ChannelUpdate1
	err := parseChannelUpdateCompatibilityMode(
		&b, uint16(b.Len()), &newChanUpdate, 0,
	)
	require.NoError(t, err, "unable to parse channel update")

	// At this point, we'll ensure that we get the exact same failure out
	// on the other side.
	if !reflect.DeepEqual(testChannelUpdate, newChanUpdate) {
		t.Fatalf("mismatched channel updates: %v", err)
	}

	// We'll now reset then re-encoded the same channel update to try it in
	// the proper compatible mode.
	b.Reset()

	// Before we encode the update itself, we'll also write out the 2-byte
	// type in order to simulate the compat mode.
	var tByte [2]byte
	binary.BigEndian.PutUint16(tByte[:], MsgChannelUpdate)
	b.Write(tByte[:])
	if err := testChannelUpdate.Encode(&b, 0); err != nil {
		t.Fatalf("unable to encode chan update: %v", err)
	}

	// We should be able to properly parse the encoded channel update
	// message even with the extra two bytes.
	var newChanUpdate2 ChannelUpdate1
	err = parseChannelUpdateCompatibilityMode(
		&b, uint16(b.Len()), &newChanUpdate2, 0,
	)
	require.NoError(t, err, "unable to parse channel update")

	if !reflect.DeepEqual(newChanUpdate2, newChanUpdate) {
		t.Fatalf("mismatched channel updates: %v", err)
	}
}

// TestWriteOnionErrorChanUpdate tests that we write an exact size for the
// channel update in order to be more compliant with the parsers of other
// implementations.
func TestWriteOnionErrorChanUpdate(t *testing.T) {
	t.Parallel()

	// First, we'll write out the raw channel update so we can obtain the
	// raw serialized length.
	var b bytes.Buffer
	update := testChannelUpdate
	trueUpdateLength, err := WriteMessage(&b, &update, 0)
	if err != nil {
		t.Fatalf("unable to write update: %v", err)
	}

	// Next, we'll use the function to encode the update as we would in a
	// onion error message.
	var errorBuf bytes.Buffer
	err = writeOnionErrorChanUpdate(&errorBuf, &update, 0)
	require.NoError(t, err, "unable to encode onion error")

	// Finally, read the length encoded and ensure that it matches the raw
	// length.
	var encodedLen uint16
	if err := ReadElement(&errorBuf, &encodedLen); err != nil {
		t.Fatalf("unable to read len: %v", err)
	}
	if uint16(trueUpdateLength) != encodedLen {
		t.Fatalf("wrong length written: expected %v, got %v",
			trueUpdateLength, encodedLen)
	}
}

// TestFailIncorrectDetailsOptionalAmount tests that we're able to decode an
// FailIncorrectDetails error that doesn't have the optional amount. This
// ensures we're able to decode FailIncorrectDetails messages from older nodes.
func TestFailIncorrectDetailsOptionalAmount(t *testing.T) {
	t.Parallel()

	onionError := &mockFailIncorrectDetailsNoAmt{}

	var b bytes.Buffer
	if err := EncodeFailure(&b, onionError, 0); err != nil {
		t.Fatalf("unable to encode failure: %v", err)
	}

	onionError2, err := DecodeFailure(bytes.NewReader(b.Bytes()), 0)
	require.NoError(t, err, "unable to decode error")

	invalidDetailsErr, ok := onionError2.(*FailIncorrectDetails)
	if !ok {
		t.Fatalf("expected FailIncorrectDetails, but got %T",
			onionError2)
	}

	if invalidDetailsErr.amount != 0 {
		t.Fatalf("expected amount to be zero")
	}
	if invalidDetailsErr.height != 0 {
		t.Fatalf("height incorrect")
	}
}

type mockFailIncorrectDetailsNoAmt struct {
}

func (f *mockFailIncorrectDetailsNoAmt) Code() FailCode {
	return CodeIncorrectOrUnknownPaymentDetails
}

func (f *mockFailIncorrectDetailsNoAmt) Error() string {
	return ""
}

func (f *mockFailIncorrectDetailsNoAmt) Decode(r io.Reader, pver uint32) error {
	return nil
}

func (f *mockFailIncorrectDetailsNoAmt) Encode(w io.Writer, pver uint32) error {
	return nil
}

// TestFailIncorrectDetailsOptionalHeight tests that we're able to decode an
// FailIncorrectDetails error that doesn't have the optional height. This
// ensures we're able to decode FailIncorrectDetails messages from older nodes.
func TestFailIncorrectDetailsOptionalHeight(t *testing.T) {
	t.Parallel()

	onionError := &mockFailIncorrectDetailsNoHeight{
		amount: uint64(123),
	}

	var b bytes.Buffer
	if err := EncodeFailure(&b, onionError, 0); err != nil {
		t.Fatalf("unable to encode failure: %v", err)
	}

	onionError2, err := DecodeFailure(bytes.NewReader(b.Bytes()), 0)
	require.NoError(t, err, "unable to decode error")

	invalidDetailsErr, ok := onionError2.(*FailIncorrectDetails)
	if !ok {
		t.Fatalf("expected FailIncorrectDetails, but got %T",
			onionError2)
	}

	if invalidDetailsErr.amount != 123 {
		t.Fatalf("amount incorrect")
	}
	if invalidDetailsErr.height != 0 {
		t.Fatalf("height incorrect")
	}
}

type mockFailIncorrectDetailsNoHeight struct {
	amount uint64
}

func (f *mockFailIncorrectDetailsNoHeight) Code() FailCode {
	return CodeIncorrectOrUnknownPaymentDetails
}

func (f *mockFailIncorrectDetailsNoHeight) Error() string {
	return ""
}

func (f *mockFailIncorrectDetailsNoHeight) Decode(r io.Reader, pver uint32) error {
	return nil
}

func (f *mockFailIncorrectDetailsNoHeight) Encode(w *bytes.Buffer,
	pver uint32) error {

	return WriteUint64(w, f.amount)
}